Few people believe it, especially men, but you don’t need barbells, dumbbells, or machines to build lean muscle in order to burn nasty fat cells.

In this post, you’ll find the last 2 laws of physics.

The first 3 laws were posted last week in detail; they are . . . Law #1: The longer your body, the weaker you become;Law #2: The farther you move, the more muscle you work; Law #3: As elastic energy decreases, muscle involvement increases.

Law #4: Moving in two directions is better than moving in one.

The science: Human movement occurs on three different geometric planes:

* the sagittal plane, for front-to-back and up-and-down movements

* the frontal plane, for side-to-side movements

* the transverse plane, for rotational movements

Most weight-lifting movements–the bench press, squat, curl, lunge, and chinup, to name a few–are performed on the sagittal plane; the balance of exercises–for instance, the lateral lunge and side bend–occur almost entirely on the frontal plane. This means that most men rarely train their bodies on the transverse plane, despite using rotation constantly in everyday life, as well as in every sport. Case in point: walking. It’s subtle, but your hips rotate with every step; in fact, watch a sprinter from behind and you’ll see that his hips rotate almost 90 degrees. By adding a rotational component to any exercise, you’ll automatically work more muscle–since you’ll fully engage your core, as well as the original target muscles–and simultaneously build a better-performing body.

Apply it: Simply twist your torso to the right or left in exercises such as the lunge, situp, and pushup. (For an example, see the “T Pushup” in “The Weight-Free Workout,” on the previous page.) You can also rotate your hips during movements such as the reverse crunch.

Law #5: The less contact your body has with the floor, the more your muscles must compensate.

The science: The smaller the percentage of an object’s surface area that’s touching a solid base, the less stable that object is. That’s why SUVs are prone to rolling, and tall transmission towers need guy wires. Fortunately, humans have a built-in stabilization system: muscles. And by forcing that internal support system to kick in–by making your body less stable–you’ll make any exercise harder, while activating dozens more muscles.

Apply it: Hold one foot in the air during virtually any exercise, including pushups, squats, and deadlifts. You can also do pushups on your fingertips or your fists.